TC115_13 Datasheet, PDF (1/14 Pages) Microchip Technology – PFM/PWM Step-Up DC/DC Converter

TC115
PFM/PWM Step-Up DC/DC Converter
Features
• High Efficiency at Low Output Load Currents via
PFM Mode
• Assured Start-up at 0.9V
• 80 µA (Typ) Supply Current
• 85% Typical Efficiency at 100 mA
• 140 mA Typical Output Current @ V_IN  2.0V
• Low Power Shutdown Mode
• No External Switching Transistor Needed
• Space-Saving SOT-89 Package
Applications
• Pagers
• Cellular Phones
• Palmtops
• 1-Cell to 3-Cell Battery Powered Systems
• Cameras, Video Recorders
• Local +3V to +5V Supplies
Package Type
SOT-89-5
PS
5
4
GND
LX
TC115
NC
PS SHDN
1
2
3
General Description
The TC115 is a high-efficiency step-up DC/DC
converter for small, low input voltage or battery-
powered systems. This device has a start-up voltage
of 0.9V and a typical supply current of 80 µA. Phase
compensation and soft-start circuitry are included on-
chip. Unlike conventional PWM step-up converters,
the TC115 automatically shifts to pulse frequency
modulation (PFM) at low loads, resulting in reduced
supply current and improved efficiency.
The TC115 requires only an external diode, an inductor
and a capacitor, while supporting typical output cur-
rents of 140 mA. Supply current is reduced to less than
0.5 µA (max) when SHDN input is brought low.
Small size, low installed cost and low supply current
make the TC115 step-up converter ideal for use in a
wide range of battery-powered systems.
Functional Block Diagram
+
1.5V
+
C₁
10 µF
L₁
100 µH
Sumida^® CD-54
D₁
5
GND
NC
IN5817 +
PS
C₂
4
47 µF
Tantalum
LX
TC115
PS SHDN
1
2
3
+3V
OUT
1.5V to +3V, 50 mA Supply
 2002-2012 Microchip Technology Inc.
DS21361D-page 1